The present invention relates to computer-implemented methods for brush-based warping including causing reflection effects in an image.
Computer painting programs allow the user to manipulate an electronic image with an onscreen “brush” controlled by an input device such as a mouse. One such program is Goo, available from MetaTools, Inc., 6303 Carpinteria Ave., Carpinteria, Calif., 93013.
The user may typically select from among a variety of brush shapes, e.g., circle, square, or single pixel. The user drags the brush along a “trajectory” from one location to another within the image, thereby defining an “envelope.” Pixels within the envelope are affected by the operation of the brush.
One type of brush allows a user to “paint” colors and textures into the envelope. The paintbrush replaces the pixels in the envelope with the image of the brush.
Another type of brush allows the user to “move” portions of the image within the envelope, creating a warping effect. For example, a “sticky” brush moves pixels from the starting point of the envelope to its end. A “slipping” brush moves the pixels from the starting point a distance less than, but proportional to, the length of the trajectory. Other warping brush effects are bloat, pucker, and twirl.